ML20002A512
| ML20002A512 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 11/23/1976 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20002A509 | List: |
| References | |
| NUDOCS 8011170431 | |
| Download: ML20002A512 (3) | |
Text
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NUCLEAR REGULATORY COMMISSION 3
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S WASHINGTON, D. C. 20555
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%, *s Ab SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT N0. 32 TO FACILITY OPERATING LICENSE NO. DPR-3 h
G YANKEE ATOMIC ELECTRIC COMPANY
$p YANKEE NUCLEAR POWER STATION (YANKEE-R0WE)
DOCKET NO. 50-29 g
Introduction By application dated October 12, 1976, Yankee Atomic Electric Company h
(the licensee) proposed changes to the Technical Specifications appended
'1 to License No. DPR-3 for the Yankee-Rowe reactor. The proposal involves a revision of the " Core XII Allowable Peak LHGR versus Exposure"
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specified in Figure 8-1, to correct an inconsistency in its application f
in the specified pro;edure ter determining the allowable fraction of full w
power.
Concurrently, the licensee also proposed the same correction in the corresponding page (Figure 3.2-1) in the new format Technical Specifications issued on July 14, 1976, with Amendment No. 27) which will Wf become effective as of January 1, 1977.
ih di Discussion y
et The licensee has reported that on August 30, 1976, during a review of the Core XII ECCS performance re-analysis, an inconsistency was discovered
/fA in application of the Core XII ECCS performance analysis results to the r?
formula for calculating the allowable fraction of full power specified in Section D.2.C(l). The licensee also reported that results of its 4
investigation show that four fuel rods (out of a total of 17,734 fuel g
rods in the core) probably operated in excess of the limiting LHGR of 10.22 m
kw/ft for a 12 day period out of the 221 power days of operation from the s$$
date of Core XII startup until August 30, 1976.
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The licensee has further reported that upon discovery of its inconsistency, power was promptly reduced by 2.7 percent and that plant operation has since then be conducted in compliance with the LHGR values (reduced by Pt h:.
2.7 percent) in the changed Figure 8-1 submitted with their October 12, 1976 application.
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Evaluation g
The licensee was authorized to operate Yankee-Rowe in the four-loop mode y,,
within the limiting Linear Heat Generation Rate (LHGR) in Section D.2.C(l) f;M' jipl w,
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Figure 8-1.
Section D.2.C.(l) also specifies that if full power cannot be kh attained within the values for the LHGR in Figure 8-1, the allowable g
fraction of full power for each type of fuel (Gulf and Exxon) shall be rac,.
calculated as follows:
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Allowable Fraction of Rf Limiting LHGR
=
h; Full power Peak Ful' Power LHGR For the above calculation the limiting LHGR is obtained from Figure 8-1.
q p The peak full power LHGR must be determined as the product of several l 4 factors including the explicit core average LHGR of 4.34 kw/ft at full W
power, all as specified in Section D.2.C.(1).
4 The values for the limiting LHGR for Core XII shown in Figure 8-1 were l[
those determined in the Core XII ECCS performance evaluation which we 4
approved prior to August 27, 1976.* These values are based on 100 percent
[ f of the fission energy being released in the fuel rods, instead of 97.3
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percent to correct for the portion of the fission energy released in the coolant and the structural material outside the fuel rods.
The licensee stated that this correction had been omitted by an error in the application M
of the computer codes.
However, the fixed 4.34 kw/ft value for the average
!:F kw/ft at full power is corrected (97.3 percent of total fission energy per IA,b linear foot) to account for fis: ion energy released outside the fuel rod.
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As a result of entering a kw/ft value based on 100 percent fission energy fgk in the numerator and a kw/ft value (4.34 kw/ft) based in the corrected AE 97.3 percent fission energy in the denominator, the calculated allowable fraction of full power would exceed the actually authorized fraction of
$t full power by 2.7 percent.
In their October 12, 1976 application, the Q
licensee proposes to reduce the values for the peak LHGRs by applying W
a 0.973 multiplier.
We have determined that this acceptably corrects
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the peak LHGR values to represent fission energy in thefuel rods (97.3 percent) which we have previously approved for Core XII and preceding
@.l cores and that it removes the inconsistency in the licensee's implementation of the Technical Specification procedure for determining the allowable fraction of full power. We therefore find that the changed Figure 8-1 is W
acceptable as proposed.
We also find that because of the short period (12 days) during which the peak LHGR may have been exceeded by a small magnitude 2*y w;
- Prior to the review reflected in this evaluation, we obtained new information h,
requiring a modification of upper head water temperature assumed in the ECCS g
evaluation for Yankee-Rowe. As a result, the NRC, on August 27, 1976, issued Lf an Order for "odification of License, further reducing the values of peak LHGR specified in Figure 8-1 by a total 0.85 kw/ft.
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This amendment correcting the peak LHGRs does not affect the requirement or conclusion in the Order of August ??, 1976.
The only effect the Order has on considerations discussed in this Safety Evaluation would be to maintain MT or reduce the peak clad temperatures found to be acceptable in the ECCS 1 7 l
performance evaluation.
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of up to two percent due to an inadvertent implementation error by the licensee, the deviation from the corrected LHGR limit was not significant g$
from a public health and safety standpoint. Accordingly, this amendment incorporates the corrected peak LHGR values in the fac,lity Technical y
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- R Specifications.
J,t We have determined that the amendment does not authorize a change in k
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effluent types or total amounts nor an increase in oower level and will not result in any significant environmental impact. Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 151.5(d)(4), that an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
Conclusion
>D We have concluded, based on the considerations discussed above, that:
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(1) because the amendment does not involve a significant increase in the
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F probability or consequences of accidents previously considered and does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities Q
X will be conducted in compliance with the Comission's regulations and the L%i issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
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Date:
November 23, 1976
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